Industrial automation has been greatly improved by using manifold assemblies that direct pneumatic pressure to control many control devices. The manifold assemblies incorporate electrical actuated solenoid valves that control the direction of pneumatic flow for actuating these control devices. These manifold assemblies are commonly assembled in modular form from a plurality of manifold blocks. The manifold assembly has a common pilot pressure passage and main pressure passages that are connected to the solenoid valves which in turn control the flow of main pressure to a respective control device. The solenoid actuated control valve has a main valve or spool and a solenoid actuated pilot valve that provides pilot pressure to the main valve. Pilot pressure to actuate a main valve is well known. If the pilot pressure connected to the solenoid actuated valves is independently supplied from the main pressure, the actuation of the main valve in the solenoid can take place only when both pilot pressure is supplied to the valve and electrical actuation of the solenoid valve occurs.
These manifolds can incorporate many manifold blocks with many valve stations and solenoid valves which in turn control many control devices. It is often desired to shut down one or more of the control devices without shutting down all the control devices connected to the manifold assembly. A shutdown may be due to routine maintenance of the device or for repairing unexpected malfunction of or damage to the device. Previous efforts to control individual valve stations were accomplished by shutting off the electrical power to an individual solenoid that controls the downstream device. The application of zoned power has also been used to control the electrical power to a group of devices in a particular zone such that only that zone may be turned off without turning off other zones of power. However, these zones of power have introduced complications to the modular assembly by increasing the number of different parts.
Manifold assemblies need to accommodate guidelines for different levels of industrial architecture that have recently been proposed or implemented. One guideline level calls for moving the solenoid valve to a mid-position to prevent pneumatic flow to the device when the device is inactivated. Another guideline level of architecture calls for detection of any movement of the device during shutdown and also provides further warning signals of the motion during shutdown. A further level or architecture calls for providing a spring loaded brake that will prevent the device from further motion when air is released for actuating the spring loaded brake.
Manifold assemblies commonly have a sandwich block interposed between a manifold block and the solenoid actuated valve. These sandwich blocks have been used to provide shut off valves for the main pressure, introduction of separate main pressure to a single valve station or to provide and isolate the exhaust of a single valve station from the manifold.
What is now desired is to provide redundancy to the architecture to further prevent inadvertent actuation of the solenoid by selectively eliminating and exhausting pilot pressure for the solenoid actuated valve. Further what is desired is both a pilot pressure system and an electrical circuit system that provides zones in the manifold assembly without the need for a great increase in inventory parts. What is further desired is a manifold assembly that can introduce a separate pilot pressure to a zone of solenoid actuated valves via a sandwich block interposed between the manifold block and the solenoid actuated valve.